First, let ’s talk about carbon. The corrosion resistan […]
First, let ’s talk about carbon.
The corrosion resistance of stainless steel balls decreases with the increase in carbon content. Therefore, most stainless steels have a low carbon content, up to 1.2%, and the C (carbon content) of some steels is even lower than 0.03% (such as 304L stainless steel balls, 316L stainless steel beads). But the general carbon content is less than 0.08%, such as 304 balls, 316 steel balls.
However, carbon content also has an incomparable effect on stainless steel balls. That is, as the carbon content increases, the hardness will also increase (requires oil quenching). This type of stainless steel typically includes 420 stainless steel beads (including 2Cr13 and 3Cr13) 420C steel balls (4Cr13) and 440 stainless steel balls (known as 9Cr18) and 440C stainless steel beads (9Cr18MO) such as 420J2 stainless steel balls generally have a carbon content of 0.26-0.35%, while 440C stainless steel balls have a carbon content of 0.95- 1.2%, which means that the hardness of 440C is much higher than that of 420J2 steel balls, and the results also show that this is correct: the hardness of 420 steel balls is usually between HRC48-55, and 440C is usually above HRC58.
Generally, carbon (C) is not shown in the grade, such as 0Cr18Ni9. The 0 actually marked on the front of the steel ball refers to the carbon content, but it does not indicate that the carbon content is 0, which is actually less than 0.08%. The preceding 00 means that the carbon content is below 0.03%, which we generally call ultra-low carbon.
Next, we will introduce another important element in stainless steel balls, nickel Ni.
Nickel mainly plays the role of rust and corrosion protection on stainless steel balls. It is bright and magnetic and is an important component of austenite. The higher the nickel content, the stronger the rust and corrosion resistance of stainless steel balls.
201 stainless steel ball <304 stainless steel ball <316 stainless steel ball
Chromium is the most important and basic component of stainless steel balls. Without chromium, it cannot be called a stainless steel ball, and the chromium Cr content must be greater than 12%. The higher the chromium content, the better the corrosion resistance of stainless steel.